in this case, this technology didn't work. i'm sure in the future they will start to work on that, see if they can do this. lots of lessons will be learned across the board. why didn't we get these people before they acted? lessons that will be critical for us to prevent something like this from happening again in the future. >> let's talk about one of those things specifically, the fbi knew about the older brother, tamerlan tsarnaev at the request of the russian intelligence service. they actually questioned him back in 2011, yet they found no reason to further investigate or apparently they asked the russians for more information and didn't get it. did they let him slip through their fingers in a way? >> the ultimate answer is yes, but we don't know where he was in 2011 and where he was in 2013. there could have been a significant radicalization. he made a trip over sees to d asha dagestan. this is a perfect storm of events that led us to the boston marathon. it would have been great if the russians gave us more information.